View Full Version : 333 FSB Athlon in 266FSB board?

03-18-03, 07:34 PM
Hi all,

I ordered a 266FSB AthlonXP2600 (T-bred core), but they sent me the 333FSB version. It is a retail box, so I cant really test it without openig it up. They will refund my money, but finding the 266FBS version seems hard these days.

I have an ASUS A7V266E motherboard, runing the 1014beta002 BIOS. Can I run this chip at 266FSB? Will it run at 16x? Or just the 12.5 x that would be appropriate to the 333FSB?

Advice please?



03-19-03, 03:11 AM
yes, of course you can run it at 266 FSB. but that will be unclocking the chip.

thus, to make up for it you will have to increase the multiplier. which may or may not work perfectly. you will have to run tests to see if your system is stable.

03-19-03, 08:45 AM
Well I managed to get the higher multipliers unlocked so that could run 133x16 instead of 166x12.5 but damned if it wont run at 133fsb. I can only get it to run at 100x20. This forces me to run the memory asychronously.

Right now I have it running at 109x20 109*20 (2180), and my memory at 145FSB (290), but running asynch like that slows the memory bandwith to be about like it is running at 125 (250) or so.

Why wont the darn thing run at 133fsb?


03-19-03, 02:30 PM
have you tried using a lower multiplier?

you cannot run at 133X16, or you cannot run at 133 at all?

03-19-03, 06:48 PM
Can not run 133 at all, with any multiplier.

Been running at 133 x 10.5 for over a year prior to this CPU.


03-24-03, 05:42 PM
Just in cast anyone is interested on how this turned out.

The reason it would not run at 133FSB at all was that it stayed locked on a 20x multiplier, giving me 2666MHz. This CPU, designed to run at 2083Mhz, just would not overclock that far. Heh

Didnt matter what I set the BIOS or Dip Switches for. Unlocked or not, the A7V266-E simply could not actually change the multipliers.

Ended up saying screw it, and hard coded a 15X multiplier on the processor so I could run ~ 148X15 giving me 2222Mhz. Running the CPU at default 1.65 voltage, and my PC2100 ram at 2.65v. Gives me decent bandwidth running at 2-2-2-6. First tried 16X multiplier but this CPU overclocks like crap, so I couldnt run at 148FSB without seriously pushing the CPU voltage. I didnt care to deal with the heat, so droped it back down.

For those that wonder, I am a crazy man and just used my pocket knife to cut the bridges (steady hands :) ), and used the ink out of a silver trace pen with the tip of my knife to close bridges. Amazingly it works fine.

This is about as fast as I am going to get with this motherboard, this RAM, and this CPU without going to voltage and cooling extremes.

It was an interesting learning process.


03-24-03, 08:02 PM
Good to hear you got it all sorted ;)